3. Asamoah Gyan

"The striker initially joined the recently-crowned Etisalat Pro-League champions on loan in September 2011 but will now remain in the Gulf state after the clubs agreed undisclosed terms."

It is understood the Black Cats received around £6million in an initial loan fee, and have accepted a similar amount to end their association with the player.

The deal which brought Gyan to Wearside in the first place amounted to in excess of £13million, although a proportion of that was dependent on add-ons which have not been triggered.

Then manager Steve Bruce signed him weeks after the 2010 World Cup finals, in which he starred for his country, although it was his extra-time penalty miss against Uruguay which effectively cost the Black Stars their place in the last four.

He was recruited to form a potentially formidable partnership with Darren Bent, and while the pair showed signs of gelling during his carefully managed early months in England, that plan was torn up when Bent submitted a shock transfer request and was sold to Aston Villa during the following January.

Gyan scored 11 goals during what proved to be his only full season on Wearside, and hit the headlines when his last-gasp equaliser denied England a friendly victory over Ghana at Wembley in March last year.

However, as his profile rose, so did interest in acquiring his services, and although Bruce thought he had fought off potential suitors last summer, he was stunned to be told the player wanted to leave for the Middle East in September.

Bruce said at the time: "I had a conversation with Gyan 48 hours ago with his agent. He shook me by the hand, get on with it, he wanted to play here, stay here because the nonsense had gone on for too long.

"I will let everybody else make their conclusions. To go and leave the Premier League for the United Arab Emirates, I will let you make your own conclusion to that.

"Sometimes things disappoint you in football which are quite unbelievable, but there you go.

"What are you going to the United Arab Emirates for? No disrespect to the country, of course."

Bruce admitted he could not see Gyan returning to the club and although his own reign was to end less than three months later, Martin O'Neill's arrival as his replacement did little to change that situation.

The striker could not be recalled under the terms of the loan deal, but as time wore on, it became apparent that his destiny lay away from Wearside.

His 22 goals for Al-Ain last season helped to secure the league title and sparked fresh interest in acquiring his signature, but the champions were always confident of retaining his services and eventually clinched the deal on Friday.

The inevitability of Gyan's departure means O'Neill's plans will not change significantly, but Friday's development serves to underline the need to find reinforcements with Nicklas Bendtner having returned to parent club Arsenal after his loan spell.

Sunderland have been heavily linked with Wolves frontman Steven Fletcher among others in recent weeks as the squad prepare to return for pre-season training next week before heading for Korea at the end of the month to take part in the Peace Cup.